Added -dir and -file options to support printing a single file or custom folder

README.md

@@ -17,6 +17,13 @@ The script checks a folder for files (intended to be set up as a cron job), if t
 
 See `main.go`, you'll probably want to edit some variables. I hacked everything together in a day for our specific case. 
 
+To inspect the possible command-line options, use `phomemoprinter --help`:
+
+- `-dir [dir]` customize the dir to scan (by default `~/Downloads/phomemo`)
+- `-file [file]` print only that image 
+
+If `-file` is used, `-dir` will be ignored.
+
 ## Launchd service
 
 To install as a `launchd` service (mac's "cron"), copy the binary to `/usr/local/bin` and the file `com.brainbaking.PhomemoPrinter.plist` to `~/Library/LaunchAgents`. Then, in a terminal, type `launchctl load com.brainbaking.PhomemoPrinter.plist`.

main.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	phomemofilter "brainbaking.com/phomemoprinter/filter"
+	"flag"
 	"log"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -12,16 +14,33 @@ import (
 )
 
 var adapter = bluetooth.DefaultAdapter
-var phomemoFolder = "/Downloads/phomemo"
 
 func main() {
-	home, _ := os.UserHomeDir()
-	inDir := home + phomemoFolder
+	var home, _ = os.UserHomeDir()
+	var defaultDir = filepath.Join(home, "Downloads", "phomemo")
+
+	dir := flag.String("dir", defaultDir, "Directory to pick up any images from")
+	file := flag.String("file", "", "Print only a specific image. If provided, -dir will be ignored.")
+	flag.Parse()
+
+	if *file != "" {
+		log.Printf("Attempting to print file %s...\n", *file)
+
+		*dir = filepath.Join(os.TempDir(), "phomemo")
+		os.Mkdir(*dir, os.ModePerm) // ignore error in case still existing
+		err := copyFileToFolder(*file, *dir)
+		if err != nil {
+			log.Fatalf("Cannot copy %s to %s: %w. Quitting. \n", *file, *dir, err)
+			os.Exit(1)
+		}
+	} else {
+		log.Printf("Attempting to scan dir %s for files to print...\n", *dir)
+	}
 
-	files, err := os.ReadDir(inDir)
-	must(phomemoFolder + " does not exist", err)
+	files, err := os.ReadDir(*dir)
+	must("Open directory target", err)
 	if len(files) == 0 {
-		log.Printf("No files to print found in %s, nothing to do. Quitting.\n", inDir)
+		log.Fatalf("No files to print found in %s, nothing to do. Quitting.\n", *dir)
 		os.Exit(0)
 	}
 
@@ -29,11 +48,6 @@ func main() {
 
 	log.Println("Scanning for Bluetooth devices...")
 	ch := make(chan bluetooth.ScanResult, 1)
-	timeout := make(chan bool, 1)
-	go func() {
-		time.Sleep(10 * time.Second)
-		timeout <- true
-	}()
 
 	go func() {
 		err = adapter.Scan(func(adapter *bluetooth.Adapter, device bluetooth.ScanResult) {
@@ -46,13 +60,27 @@ func main() {
 	}()
 
 	select {
-	case device := <- ch:
-		log.Println("Found device: ", device.Address.String(), device.RSSI, device.LocalName())		
-		tryToPrint(device, inDir, files)
-	case <- timeout:
+	case device := <-ch:
+		log.Println("Found device: ", device.Address.String(), device.RSSI, device.LocalName())
+		tryToPrint(device, *dir, files)
+	case <-time.After(10 * time.Second):
 		log.Fatal("Timeout trying to locate Phomemo M02, is it on? Quitting.")
+		os.Exit(1)
+	}
+}
+
+func copyFileToFolder(file string, folder string) error {
+	contents, err := os.ReadFile(file)
+	if err != nil {
+		return err
+	}
+
+	err = os.WriteFile(filepath.Join(folder, "toprint.jpg"), contents, os.ModePerm)
+	if err != nil {
+		return err
 	}
 
+	return nil
 }
 
 func tryToPrint(phomemoAddress bluetooth.ScanResult, dir string, files []os.DirEntry) {
@@ -78,7 +106,7 @@ func tryToPrint(phomemoAddress bluetooth.ScanResult, dir string, files []os.DirE
 	chars, err := srvc.DiscoverCharacteristics(nil)
 	must("failed to discover characteristics of service", err)
 
-	pyfilterloc := dir + "/" + "phomemo-filter.py"
+	pyfilterloc := filepath.Join(dir, "phomemo-filter.py")
 	dumpFilter(pyfilterloc)
 	defer func() {
 		os.RemoveAll(pyfilterloc)
@@ -89,7 +117,7 @@ func tryToPrint(phomemoAddress bluetooth.ScanResult, dir string, files []os.DirE
 		filePath := dir + "/" + file.Name()
 		if isPossibleToPrint(filePath) {
 			writeData(pyfilterloc, filePath, chars[1]) // 0000ff02-...
-			readResult(chars[0])          // 0000ff01-...
+			readResult(chars[0])                       // 0000ff01-...
 			os.RemoveAll(filePath)
 		}
 	}
@@ -144,6 +172,7 @@ func readResult(char bluetooth.DeviceCharacteristic) {
 
 func must(action string, err error) {
 	if err != nil {
-		panic("failed to " + action + ": " + err.Error())
+		log.Fatalf("Fatal error: Failed to "+action+": %w \n", err)
+		os.Exit(1)
 	}
 }